textproduct: Albany

WHAT HAS CHANGED

SPC has placed a Marginal Risk for isolated severe thunderstorms for areas mainly south and east of Albany for Sunday (Day 3). Have also lowered forecast max temps from NBM Sunday due to expected cloud coverage and some showers/thunderstorms.

KEY MESSAGES

1) After a mainly dry Saturday, at least showers/thunderstorms arrive late Saturday night and continue through Sunday afternoon, with isolated severe thunderstorms possible Sunday afternoon.

2) Cooler than normal temperatures are expected through early next week, with shower chances persisting especially areas near and north of I-90.

DISCUSSION

KEY MESSAGE 1...

After a relatively dry Saturday with increasing clouds, showers develop from southwest to northeast across the region Saturday night, mainly after midnight. There remains uncertainty regarding how widespread shower coverage and intensity become, as some higher-res CAMs suggest a weak wave of low pressure tracks northward along mid Atlantic coast into southern New England, potentially bringing a swatch of locally moderate to heavy rain across portions of eastern NY. Will need to watch trends over the next 24-hours to see if these more extreme CAMs are being influenced by convective feedback processes or not. 12Z/21 HREFs indicating 6-hour probs for >1"/rainfall ending 8 AM Sunday at 20-30%, and 10-20% for >2" during this time period, mainly reflecting the higher QPF CAMs.

After the initial showers/embedded thunderstorms early Sunday morning, an occluded front is expected to cross the region between mid morning and mid afternoon. Depending on the timing of this front, there is a possibility for enough instability (CAPES 500-1000 J/kg) to build amid 0-6 km shear of 35-40 KT for some stronger low-topped thunderstorms to develop. Instability is greatest for areas mainly south and east of Albany during Sunday afternoon, assuming a slower frontal passage. However, upper level forcing looks stronger across the SW Adirondacks and Mohawk Valley region. SPC Day 3 convective outlook has placed areas mainly south/east of I-88 in the Marginal Risk for severe thunderstorms, mainly for isolated instances of damaging wind gusts, as well as severe hail given the deep layer shear and cooling mid levels.

KEY MESSAGE 2...

Upper level low/cold pool across the eastern Great Lakes region will slowly meander north/northeast early next week, allowing below normal temperatures to persist. In addition, as weak upper level disturbance pivot around the eastern periphery of the main upper level low, forcing and shallow instability will allow for scattered showers and possible low-topped thunderstorms Monday afternoon/evening, and perhaps again late Tuesday, especially areas near and north of I-90 in closer proximity to the upper level low. Can not rule out some locally gusty winds and small hail within any taller convective elements/clusters that develop.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Through 18z/Saturday...With high pressure overhead, VFR conditions will prevail across all the terminals through most of the TAF period. Current satellite imagery shows mainly SKC skies with FEW/SCT fair weather cumulus passing through this afternoon. Cloud cover increases overnight into tomorrow ahead of an upper level low tracking to our south tomorrow. Model soundings hint at the possibility of fog/mist developing at KGFL and KPSF near sunrise tomorrow morning, however there will be more confidence in the following TAF cycles. Northeast winds this afternoon and evening remain 5-10 kt before becoming light and/or calm overnight. Winds then shift out of the southeast 5-10 kt by tomorrow mid morning.

Outlook...

Saturday Night: Moderate Operational Impact. Chance of SHRA. Sunday: High Operational Impact. Definite SHRA...TSRA. Sunday Night: Low Operational Impact. NO SIG WX. Monday: Moderate Operational Impact. Chance of SHRA...TSRA. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.